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By A Campbell

Trials of different tapping operations at Olympic Dam have been carried out with the aim of improving the safety of tapping and improving the integrity and lifetime of the taphole. This has involved trialling the use of a mudgun and drill on one of the tapholes of the electric furnace in place of the normal manual tapping procedures. The blister copper tapholes are currently closed using a conical clay plug formed around a steel bar. The plug is pushed into the taphole by hand to stop the flow, and the cooling on the outer part of the taphole freezes the blister copper in the tapping channel. The hole is burnt open using consumable oxygen lances. This puts the furnace technicians in close proximity to molten metal and heat û which is reflected in the safety incidents reported by these operators. By moving to a mudgun and drill operation, the furnace technicians will be moved away from the taphole area improving their safety. Additional benefits include: improved tapping cycles; extended taphole refractory lifecycles; and improved furnace integrity around the taphole, hopefully extending the campaign. This paper outlines the trials that have shown that it is possible to plug and drill blister copper (not matte) tapholes using a mudgun and drill.

Jan 1, 2005

By H Höft

Today tunnel segment liners are sealed with corner-vulcanised gaskets made of extruded elastomeric compression profiles. The profile geometries and the elastomeric materials have been further developed in course of time to meet the steadily increasing water-proofing requirements. After 40 years of using such compression gaskets, a wide range of proven standard profile geometries and well-known brands can be found on the market. Even so, there is still potential for further developments and improvement, not only with regard to the water-proofing performance. Permanently increasing cost pressure in the segment production plants demands further developments and new solutions with regard to application techniques. This is an abstract only. No paper was prepared for this abstract.

Mar 8, 2011

By Richards JR, Herbert HK

A basic question in preparing this review was how to define sulphur mineral occurrences as being associated with the Pacific Rim. This question will be reconsidered later. The isotope composition of sulphur- containing minerals may be considered in terms of two primary sources - 1. deep- seated sulphur, devoid of crustal contam- ination with a 634S value near 00/0o and 2. oceanic sulphate which fluctuated in value between +10 and +300/00 over geological time (Claypool et al., 1980). However, minerals have seldom been directly derived from these primary sources as even evaporites have been dissolved and reprecipitated. The marine source is differentiated biochemically and isotopically in recent sediments where sulphide from bacterial sulphate reduction may be significantly depleted in 31S. The question of chemical interaction of ascend- ing magma with upper crustal rocks has become one of degree rather than whether or not it occurs. Mineral deposition is considered increasingly in terms of mixing of fluids and their chemical reactions with rocks rather than direct precipitation from magmas or hydrothermal fluids derived from them.

Jan 1, 1987

An image analysis system has been built which automatically digitizes camera input of rock fragments, analyses the digitised data to determine the sizes and shapes of the rock fragments, and outputs the analysed data to a printer in the form of a histogram or a scatter chart. The high speed of such a system allows for direct collection of data from material thrown into the air by blasting, material travelling on a conveyor belt, and material free-falling on to a stock-pile or into or out of a rock-crusher. Data on the blasted, un-crushed material provides information on changes in the lithology and structure of the rock face as it is quarried or mined: flatter fragments may represent approach to a brittle, unstable shear zone, or a change from sandstone to shale; so that the informa- tion reflects the effect on the sizes and shapes of the fragments by the blasting process and/or by the rock structure. The size and shape distributions of rock fragments produced during blasting and during processing may now be continuously monitored. Such detailed analysis of the results of fragmentation is labour-intensive and expensive when the size and shape distributions are obtained manually, but is cheap and efficient when using this image analysis system. Such a system will enable the results of blasting, quarrying, mining and crushing to be cheaply analysed and correlated with current and changing indus- trial practice so leading the way to increased productivity.

Jan 1, 1988

At the treatment plant of the Broken Hill South Limited, Broken Hill, the zinc concentrates, with water, are pumped out to a more or less level area, and stored in dams to dry by drainage and evaporation.In-the construction of these dams a clay bank is first thrown up around the proposed dam site. The concentrate and water mixture are then run in from the perimeter, the solids being continuously shovelled up to increase the bank height, while the clear water is drained off at the centre and returned to the treatment plant.These dams vary in size up to 57,000 sq. ft. in area; when completed the banks are about 12 it. high, and the capacity for the largest dams is about 350,000 cub. ft., say, 20,000 tons.The survey office is called upon for a monthly survey of these dams, generally three of which are in process of building or refilling. The puggy nature of the material prohibits walking beyond the bank of the dam, therefore the following method of estimating concentrates was evolved. No originality is claimed, but as the need is for a true survey, and the results have shown the accuracy of the method, a description is warranted. The dam site is first laid out into 10-ft. squares with a theodoliteand 150-ft. steel tape, the outside lines being placed about 15 ft. from the clay bank - 15 ft. is the maximum convenient distance from the bank for working with the levelling staff mentioned later.As the dam is rarely rectangular in plan, the outside points pegged out are not always the corner of a square, but are placed to give the greatest convenience in later work, that is to say, there may be triangles and irregular figures. The plan (Fig. 1) and photographs (Figs. 5 and 6) will give the general idea of the layout. At each point is driven a 3 ft. 6 in. round iron peg about 3 ft. into the ground. This peg is to permanently mark the point, and is not liable to be...

Jan 1, 1925

By Walker E. R

IN the early age of steel it was made hy what is known as the cementation proeess, in which wrought iron was embedded in charcoal and heated in a mufflc furnace to a tcmperature of approximately 1100° C. for varying lengths of time, the length of time depending upon the amount of carbon (or better known in thosedays as the degree of hardness) required in the finished product.By this process the resultant product obtained was not of uniform quality, and because of this uncertainty of quality Huntsman was induced, in the year 1740, to introduee what is known as the crucible process.This process consisted of cutting into small pieces the product of the cementation process, placing these pieces in a crucible, and melting them down with the aid of a eoke-fired furnace, after which the molten metal was cast into suitahly shaped ingots, from which could be hammered any desired shape.A section of crucible furnace is shown in Fig. 1. By this means a product, very uniform in character, was produced.The process is still in use, but, owing to its high operating cost, it is mostly eonfined to the production of very high-grade carhon and alloy steels. Its position to-day as a producer of these high-grade steels is, however, being very seriously challenged by the electric process.It was owing to the excessive cost of crucible steels and the need of producing a steel in commercial quantities and at a reasonable cost, that led Sir Henry Bessemer to introduce what is known as the Bessemer process.

Jan 1, 1930

The fundamental features of the Cable Belt Conveyor are described. It consists of independent wire ropes which take the transmission load, and a special reinforced rubber belt which acts 'only as carrier of material. The first cable belt installation in Scotland is described briefly.A general description of this type of conveyor is followed by details of the rubber belt construction and the method of joining sections of belt. The drive unit, the tensioning arrangements and the power requirements are outlined.Applications of the cable belt conveyor are 'dealt with and its advantages summarized.INTRODUCTIONThe cable belt conveyor, as its name implies is a conveyor composed of steel wire ropes and a rubber belt, in which the ropes serve as transmission members, and the belt merely as a carrier of materials.Over the years it has been the ambition of engineers connected with the belt conveyor industry to develop a conveyor that would use the high tensile strength of wire ropes to transmit the stresses involved in the driving of large capacity belt conveyors. Different lines of approach have been adopted in the United States of America and in Britain. In the United States the method adopted was to introduce a large number of flexible steel cables into the rubber belt itself, in the form of a closely packed layer arranged across the full width of the belt. These small cables are packed in a nylon filled duck envelope which is incorporated in the rubber belt. This is commonly known as the steel corded conveyor belt. In Britain, a Scottish firm developed a rubber belt conveyor in which full advantage was taken of the high tensile features of wire rope, without embodying or moulding the wire rope into the rubber belt, so that the two wire ropes and the rubber...

Jan 1, 1957

By Misra VN

The carbon-carbon dioxide reaction is the rate determining step in industrial processes such as the rotary kiln direct reduction process for iron ores. The use of brown coal as a reductant in the rotary kiln process has been shown to result in higher throughputs and lower kiln temperatures. No experimental data has been reported on the effect of coal type or the use of brown coal chars. Methods of carbon-carbon dioxide reacti- vity measurement are discussed. None of the methods have been related to direct reduction practice. No standard test has been developed to assess the reactivity of brown coal chars to carbon dioxide. For routine comparative work the gas analysis method of Okstad and Hoy appears to be the most suitable although some modification to the experimental conditions is required. For detailed kinetic studies direct weighing techniques are to be preferred. The factors affecting the reactivity of brown coal char to carbon dioxide are reviewed. Numerous factors such as the origin of the coal, pretreatment and ,physical and chemical differences have been found to affect the reactivity of brown coal chars but no data has been reported on the effect of coal type on reactivity to carbon dioxide.

Jan 1, 1980

A simple method of designing effective fill drainage systems for slurry backfill is presented. By using the proposed method, it is easy to calculate and predict the expected fill drainage rates or to provide additional drainage systems to accelerate the fill drainage. The fundamentals of hydraulic fill and an efficient method to determine its permeability is also explained. The safety in hydraulic filling and bulkhead stability depends totally on achieving effective drainage regime for the fill. This paper provides the basis for creating such efficient drainage regimes. The recent fatal fill bulkhead failures in Australia were the result of poor drainage from the respective fill masses, and therefore it is more important to provide suitable drainage arrangements to continue using hydraulic fill to the benefit of the mining industry. At present there is no procedure available to mine operators to estimate the expected bulkhead pressures to design a satisfactory bulkhead. Some mines are constructing bulkheads after their initial investigations carried out years ago. Other mines have simply borrowed the ideas from the pioneer mines and using in their areas. It is high time that we develop a rational approach to estimate the expected bulkhead pressures for the design of bulkheads. We need a simple model that could be understood and used by the mine operators on a day-to-day basis. This paper also presents a model to predict the bulkhead pressures for designing safe bulkheads.

Jan 1, 2002

By Eggins SM, Crawford AJ, Wallace ME, Falloon TJ

The Earth's Upper Mantle is dominantly peridotitic but in convergent margin regions, such as the S.W. Pacific, subduction of oceanic crust gives greater chemical and petrological diversity to upper mantle petrology and petrogenesis. Examination of currently active, Quaternary and Tertiary volcanism in the S.W. Pacific, particularly seeking information from ocean floor sampling to characterize the basement to island arcs and to investigate active spreading centres, consistently points to parental magmas of basaltic to picritic character. However, these parental magmas are chemically diverse and it is not possible to designate a characteristic 'island arc' or 'convergent margin' petrogenesis in the sense of a characteristic mantle source composition and a charactistic partial melting regime. In this respect, magma genesis at convergent margins contrasts with that at oceanic spreading centres. Our studies emphasize the importance of source peridotite ranging from 'fertile lherzolite' (i.e. compositions with 3-4% CaO, A12O3, 0.3-0.5% Na2O) to refractory harzburgite (

Jan 1, 1987

Mine geologists have access to an economic mineral deposit, production parameters and secure exploitation title. They are well placed to understand ore formation and should contribute to the effective exploration of company mine property. Application of their special skills has been curbed by pre-occupation with production duties and by company re-engineering, including staff reductions. Contributions to exploration have been diminished and personal development inhibited. Modified management is required. Participation in mineral system studies and in exploration research comprise part of the basis for the re-emergence of mine geologists on the exploration scene. Changes in investment strategies in the minerals industry may create new employment opportunities. With regard to estimation of resources and reserves, the competence of practitioners who are incapable of disclosing their methods in transparent terms is under question. Ethical standards are also under public scrutiny because of some notable malpractice. Independent auditing may hecome more intrusive. While understandable in a market context, it reflects poorly on the profession. More substantial effort in public communications can improve the credihility ofthe industry and equip practising mine ceolouists for snider responsihility.

Jan 1, 1997

Geotechnical input is interwoven into the mining process at George Fisher South Mine from the planning and design of working areas to the closure of worked out areas and maintenance of life of mine and long term excavations. The methodology used consists of a mixture of application of established theoretical principles and guidelines derived from successful historical experience. In the development stage, including long term infrastructure excavations, the process takes into account the expected life of the excavation, usage and expected stress changes during its life span. On the stoping stage, the design process takes into account the local rock mass conditions, geological structure setting and previous experience in a particular orebody. Due to the high variation in age of currently used excavations, a rolling monitoring and risk assessment process for long term and life of mine excavations and infrastructure is maintained. This paper has as an output the process that must be followed to ensure an excavation on the highly dynamic mining environment at George Fisher South Mine is blasted and maintained in compliance with applicably commonly accepted safety and industry requirements.

Nov 25, 2010

By A Robertson

Australia has been slow in adopting the use of underground space as a part of our urban planning process. Australia has one of the highest levels of tunnel advance per capita per annum in the world, yet the use of underground space in our cities appears difficult for our planners and politicians to comprehend, not withstanding the general availability of good quality rock and contractor expertise in Australia. However, the lack of space in our urban areas is being highlighted as our major cities expand outwards and people and businesses gravitate towards city centres. Typical potential underground space uses include car parking, self-storage and archiving facilities, water storage, underground quarrying, small industrial facilities and another layer of traffic (electric and fuel cell) and services network. Historically, blasting in high density population areas has resulted in blast vibrations and blast overpressures exceeding the limits, which in some case have been set extremely low in terms of peak particle velocity (PPV). This makes conventional blasting difficult, often requiring low charge weights per delay and associated small blast sizes and slow advance rates. However, the introduction of new technologies, such as computer aided drilling, electronic delays and low-energy explosives has made this task considerably easier. Although more expensive than conventional blasting, excavation by blasting using these products and technologies in relatively good quality ground is believed, in most cases, to be less than the cost of mechanical excavation. In this paper, the authors look at innovative trends in underground quarrying, underground commercial space and tunnelling and put forward their concept of future excavation demand, future product requirements and technical specifications to the drill and blast community.

Jan 1, 2007

By J Moncrieff, P Bellairs

The Black Star Open Cut is located immediately adjacent to the township of Mt Isa and is situated in the middle of extensive pre-existing infrastructure including two concentrators, two smelters, a wet fill plant and two shafts. At any one time there are in excess of 500 people working on the surface within an industry-accepted 600 m exclusion zone from Black Star blasts. Apart from the surface operations there are also the underground operations including the lead mine (closed in December 2005) and the Enterprise and X-41 mines that must clear for all Black Star blasts. The application of industry standard blasting exclusion zones (600 m) was risk assessed as imposing operationally prohibitive constraints which could cause significant business interruption due to the logistical challenges required to ensure that all personnel from surface plants were evacuated for each blast and potential for lost production whilst these personnel were not operating the plant. In was therefore an imperative for the blast exclusion zone to be reduced. This was achieved by the: use of a QA/QC team to ensure that relevant drill and blast implementation is within an acceptable tolerance (KPIs) from design; use of high-quality stemming material called HMR, which is a by- product of the concentrating process and is generally sized at -14 mm with very little fines; implementation of appropriate training and support to Black StarÆs own blast crews, reinforcing the need to achieve the designed amount of stemming in every hole; and provision of appropriate support from Black StarÆs management for additional resources to ensure that every blast achieves design within the KPIs but especially in high-risk areas. The blast exclusion zone was successfully reduced after monitoring the flyrock results from more than 176 blasts. Black Star Open Cut now maintains a minimum blast exclusion of 200 m in critical areas; however, general blasting currently uses a 250 m exclusion as this provides additional risk management whilst still minimising the logistics associated with clearing and securing the slightly increased area.

Jan 1, 2007

The excessively high cost of production in underground coal mines has made the survival of many coal mines around the globe economically non-viable. The global competitive coal market speaks itself of the desirability of a lower operating cost in conjunction with a higher productivity performance, particularly in underground coal mines, and calls for an optimal production planning under a host of constraints. Such a task of optimal planning is not an easy exercise like that of traditional planning based merely on intuition, experience and subjective judgement. It essentially demands a thorough understanding of the complex interaction of mine sub-systems for judicious application of optimisation tools and techniques available with operations research. A few large mines around the globe have made an effective use of a sizeable number of operations research packaged programs for optimal decision-making (Grayson, 1989). The success of practical applications of operations research techniques made in a variety of mining problems in large mines in different parts of the world will hopefully make inroads to smaller mines in years to come. The present paper is an addition in the series of such applications of operations research tools to mining problems, particularly with reference to an underground coal mine in India. The paper is based on research work (Jawed, 1990) and deals with the development and use of a mathematical model for production planning in underground coal mines under multiple objective environment subject to a host of constraints.

Jan 1, 1995

By Read T. A

PART 1The quantity of dust present and the methods used for suppression of dust in metalliferous mines has, in recent years, received considerable attention from mining engmeers in various parts of the world. Shortly after the publication of the General Report of the Miners' Phthisis Prevention Committee, South Africa, in 1916, the officers of the Broken Hill South Limited started investigations into the conditions of the dustiness of the air in the underground workings. As the methods used are not generally known in Australia, the writers are of the opinion that the present is an opportune time to place them before members of the Institute. A large amount of the subject matter of this paper has been drawn from the 1916 and 1919 reports of the Miners' Phthisis Prevention Committee, South Africa, the paper of Mr. Innes published in "The Chemical, Metallurgical and Mining Society of South Mrica"; also various articles appearing in the Journal of Industrial Hygiene, and the American Journal of Public Health. A great deal of research work into the cause, prevention and estimation of mine dust has been made by the Miners' Phthisis Prevention Committee of South Africa, and officials of the United States Bureau of Mines. The writers considered it advisable to begin the investigation at the South Mine with apparatus and methods developed by the South African Committee.Through the Australian agent of the Cape Explosives Company, inquiries were made preliminary to procuring the necessary apparatus for the determination of dust, from South Africa. The writers then learned that the older gravimetric method used by the Phthisis Prevention Committee was likely to be superseded by the konimeter...

Jan 1, 1922

By J Araya, O Leiva

The mine evaluation process, composed of the designing, planning and valuation of a mine project, is, among other variables, based on an estimated orebody model. However, as the information from the drill holes is limited, it is impossible to know with certainty the mineral content in each block within the estimated block model. Consequently, uncertainty about the value of metal grades, or other geological attributes, arises because of the lack of information at unsampled locations. This is one of the reasons why, in any mine operation, there will always exist a divergence between estimated and real values. Cut-off grade optimisation is the process used to determine the operating mining strategy (long-term production scheduling) that will maximise the total profit value (normally referred as the net present value (NPV)) of a mine operation. This is done by defining a dynamic cut-off grade policy which is constrained by the production capacity of the mining, mill and refining.Real options is a type of contract, written on real assets such as mining, oil and other natural resource industries, that gives you the right but not the obligation to exercise the contract. It is based on operational and managerial flexibility, which allow mine decision makers to react to either good or bad operational and economic events in the future. But, what do geostatistics and cut-off grade optimisation have to do with the application of real options in a mine project evaluation process? The objective of this paper is to answer the previous question by showing how geostatistics combined with cut-off grade optimisation are key tools for corporate/managerial decision makers, which allow them not only to analyse the resource/reserves of their projects, but also to generate operational strategies that can maximise project value by minimising the downside risk due to ore tonnes and grade uncertainties, while achieving operational and physical constraints such as mining and processing capacities. A real copper grade open pit mine project is used as a case study.

Sep 26, 2011

In recent times there has been a marked increase in public awareness of air pollution. Some of this has been induced by the Press but our own senses tell us that there is a visible haze over our cities on many mornings. The people are now demanding a clean environment and will no longer tolerate smoke and dust fall or gaseous and odorous emission which either soil building and furnishings or interfere with comfort and well being.

Jan 1, 1971

Atlas Copco is one of the worldÆs leading providers of industrial productivity solutions (Atlas Copco, 2009). Furthermore, the company spans 160 markets and held 34 000 employees at the end of 2008. The company is organised under three ætechniquesÆ whereby the Construction and Mining TechniqueÆs business division is located within +rebro, Sweden. This paper is aimed at briefly facilitating information on how the company and more specifically, the Construction and Mining Technique is run. Also, by sharing my experiences, this paper is intended to encourage and motivate students currently studying for a degree relevant to the minerals industry, to apply for this extremely beneficial scholarship. Through a number of presentations relating to the various divisions, products and aftermarket services of the company, I came to realise that Atlas Copco extends beyond simply selling equipment suitable for the mining and civil industries. This tour through Sweden also contained highlights of visiting the Underground Rock Excavation factory, Surface Drilling Equipment factory and Secoroc divisions. I was also fortunate enough to participate in a tour of the LKAB mine in Kiruna. In addition, time was allocated to less industry related activities, and I was able to go dog sledging, sip vodka cocktails out of ice glasses at the Ice Hotel and enjoy traditional Swedish foods of moose and reindeer. Most important and memorable to me; however, was the ability for employees of Atlas Copco to speak of the company and their products with such passion and enthusiasm, which truly made this a motivational and unforgettable experience.

Jan 1, 2009

The Kelian gold mine which was developed in East Kalimantan Indonesia in 1990 - 1992 is scheduled to complete mining and processing operations in 2004. This will have a major impact on the neighbouring communities who have benefited from the jobs, economic activity and infrastructure development which has been generated by the mine. Currently, there are no formal regulations or standards specifying the procedures for relinquishment of mining leases in Indonesia. Furthermore, a move towards regional autonomy, providing greater authority and responsibility to local (regional) areas, has recently been implemented in Indonesia and limited capacity exists in the new regional governments. Consequently, in October 2000, Kelian Equatorial Mining (KEM) initiated a partnership with the local community and government to explore sustainable post-closure options for the mine site and community development programs. The Kelian mine closure strategy seeks full involvement of all stakeholders through the Kelian Mine Closure Steering Committee (MCSC) in the development of sustainable solutions which will enable communities to secure long-term benefits and minimise post-closure risks from the KEM operations. This organisation, jointly chaired by the Head (Bupati) of the regional West Kutai government and the KEM President Director, with representatives from the local communities, governments and NGOs, has developed a Charter, a website and evaluation criteria to ensure accountability and transparency. There are four technical working groups, consisting of representatives from the mine, local community leaders, NGOs, Universities, Local, Provincial and Central Government Departments, which report to the Steering Committee. These working groups have researched, developed and recommended sustainable options to the Steering Committee. The MCSC has met quarterly to examine options in accordance with the criteria set out in the Charter and has endorsed sustainable solutions which have support from Government, Community and the mine. This paper describes the closure risks, sustainable outcomes derived through the Kelian mine closure steering committee process and outlines the methodologies used to develop and endorse sustainable solutions in a society with limited capacity undergoing enormous change and uncertainty.

Jan 1, 2003